From 25e5429227147e774ef957d4677625ca00ac6195 Mon Sep 17 00:00:00 2001 From: Martin Thomson Date: Wed, 13 Jan 2021 11:30:12 +1100 Subject: [PATCH 1/3] Make a new paragraph --- draft-ietf-quic-transport.md | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/draft-ietf-quic-transport.md b/draft-ietf-quic-transport.md index c0514dabbe..1354ccc48a 100644 --- a/draft-ietf-quic-transport.md +++ b/draft-ietf-quic-transport.md @@ -4217,11 +4217,13 @@ to at least the smallest allowed maximum datagram size of 1200 bytes by adding PADDING frames to the Initial packet or by coalescing the Initial packet; see {{packet-coalesce}}. Similarly, a server MUST expand the payload of all UDP datagrams carrying ack-eliciting Initial packets to at least the smallest -allowed maximum datagram size of 1200 bytes. Sending UDP datagrams of this size -ensures that the network path supports a reasonable Path Maximum Transmission -Unit (PMTU), in both directions. Additionally, a client that expands Initial -packets helps reduce the amplitude of amplification attacks caused by server -responses toward an unverified client address; see {{address-validation}}. +allowed maximum datagram size of 1200 bytes. + +Sending UDP datagrams of this size ensures that the network path supports a +reasonable Path Maximum Transmission Unit (PMTU), in both directions. +Additionally, a client that expands Initial packets helps reduce the amplitude +of amplification attacks caused by server responses toward an unverified client +address; see {{address-validation}}. Datagrams containing Initial packets MAY exceed 1200 bytes if the sender believes that the network path and peer both support the size that it chooses. From 2000306a1d49c91f7fdcf38e7912a19610b1762c Mon Sep 17 00:00:00 2001 From: Martin Thomson Date: Wed, 13 Jan 2021 11:32:52 +1100 Subject: [PATCH 2/3] Padding with invalid packets is OK Closes #4738. --- draft-ietf-quic-transport.md | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/draft-ietf-quic-transport.md b/draft-ietf-quic-transport.md index 1354ccc48a..bba0243222 100644 --- a/draft-ietf-quic-transport.md +++ b/draft-ietf-quic-transport.md @@ -4215,9 +4215,10 @@ meet size constraints; the endpoint MAY however discard such datagrams. A client MUST expand the payload of all UDP datagrams carrying Initial packets to at least the smallest allowed maximum datagram size of 1200 bytes by adding PADDING frames to the Initial packet or by coalescing the Initial packet; see -{{packet-coalesce}}. Similarly, a server MUST expand the payload of all UDP -datagrams carrying ack-eliciting Initial packets to at least the smallest -allowed maximum datagram size of 1200 bytes. +{{packet-coalesce}}. Initial packets can even be coalesced with invalid +packets, which an receiver has to discard. Similarly, a server MUST expand the +payload of all UDP datagrams carrying ack-eliciting Initial packets to at least +the smallest allowed maximum datagram size of 1200 bytes. Sending UDP datagrams of this size ensures that the network path supports a reasonable Path Maximum Transmission Unit (PMTU), in both directions. From 819965c05abb1bd7d52795af1eb35f309bcbdd26 Mon Sep 17 00:00:00 2001 From: Martin Thomson Date: Wed, 13 Jan 2021 11:41:34 +1100 Subject: [PATCH 3/3] will Co-authored-by: Jana Iyengar --- draft-ietf-quic-transport.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/draft-ietf-quic-transport.md b/draft-ietf-quic-transport.md index bba0243222..36f3fc723f 100644 --- a/draft-ietf-quic-transport.md +++ b/draft-ietf-quic-transport.md @@ -4216,7 +4216,7 @@ A client MUST expand the payload of all UDP datagrams carrying Initial packets to at least the smallest allowed maximum datagram size of 1200 bytes by adding PADDING frames to the Initial packet or by coalescing the Initial packet; see {{packet-coalesce}}. Initial packets can even be coalesced with invalid -packets, which an receiver has to discard. Similarly, a server MUST expand the +packets, which a receiver will discard. Similarly, a server MUST expand the payload of all UDP datagrams carrying ack-eliciting Initial packets to at least the smallest allowed maximum datagram size of 1200 bytes.